The restaurant and fast-food industry require apparatus for holding food and for cooking purposes. A conventional oven does not hold food well because food retained therein for an extended length of time tends to dry out and merely adding moisture to food in this environment produces only soggy food. The blowing of any appreciable amounts of heated air over and in direct contact with the food for holding or cooking purposes tends to dry out the food. Heat lamps generally fail to retain a desirable internal continuous temperature and further they also tend to dry the food.
In earlier patents of the assignee of the present invention, including U.S. Pat. Nos. 3,868,941, 3,955,007, 3,999,475, 4,039,776, and 4,062,983, apparatus and methods are described for food holding purposes in which a stream of circulating air that has been heated and/or moisturized is passed around a stable inner core of air surrounding the food without a significant amount of airflow in direct contact with the food.